1. Field of the Disclosed Embodiments
The disclosure relates to air traffic management.
2. Introduction
The cost of operating a flight may be decomposed into the cost of the fuel used and other direct and time-related costs, such as crew pay and aircraft maintenance costs. In advanced flight management systems (FMS) the Cost Index (CI) is a parameter that embodies the relative cost of fuel and the other direct and time-related costs; this parameter is used by the FMS to build the business reference trajectory according to operator preferences. The CI is often considered proprietary information by airlines as it embodies important strategic information related to the airline operational costs. Moreover, the specific relationship between cost index and airspeed varies from aircraft type to aircraft type and is a function of many variables such as gross weight, wind, temperature, altitude, and other factors, such as actual engine performance (for example, the actual fuel flow of an aircraft engine changes significantly over its lifetime).
On the other hand, to maintain safety and separation between aircraft, air traffic controllers and managers have to adjust flights with tactical and strategic changes, and the lack of knowledge of the user preferences that apply to each individual flight means that no effort is (or can be) made to reduce or minimize the costs of these changes to the operator. While exerting changes to the flight the controller has available several degrees of freedom (DOF) to direct those changes, including horizontally (such as lateral offsets or “direct-to” instructions to go straight to a down-route waypoint), vertically (such as altitude changes, either up or down), or temporally (via Required Time of Arrival, or more traditionally speed changes). However in many situations it is difficult or even impossible to determine which of the possible DOFs (or combination thereof) results in the minimal deviation from the reference business trajectory, or user preferences.
In principle, if the controller had access to the user preferences embodied in the CI information, he or she could take that information into account when deciding which of the available DOFs to exercise when a flight maneuver is required. In practice, however, CI is not available to the controller and even if a mechanism to provide CI information was available, airlines are reluctant to disclose it. Moreover, the mechanism to translate CI to the impact on operating cost of different types of maneuvers may be proprietary to the aircraft Original Equipment Manufacturer (OEM), and may not be able to be used by controllers or decision support tools (DST) directly. In trajectory based operations (TBO), user preferences are the driving force behind operations, where all operations should be based on trajectories that reflect operator business objectives. Thus, a method is needed for airlines to express their business preferences that is effective (i.e. it can be readily used by ground automation), is universally understood (i.e. it does not rely on operator or OEM unique translation), and that does not reveal strategic or proprietary information about the operator.